2006 50hp EFI 4-stroke fuel problems

[Fishing4fun]

After all the other troubles I have I had, I thought I had everything back to going. Went back on the lake today and I can't get WOT without the gaurdian alarm going off. Again, it goes beep...beep...beep...beep about every second. There is no certain number of beeps. It will just continue to beep every second until I turn the key switch off. It acts as if it is vapor locking because I can seem to run around 2000 rpms all day long but as soon as I start trying to open it up, the alarm goes off. I tried to keep going at WOT once and the motor shut off after about 3 seconds. I restarted just fine and I could still run about 2000 rpms without any trouble. I have totally pulled every filter, every line, and even the VST and checked for obstructions and cleanliness and found nothing. The CDS diagnostic system doesn't show any errors. Could I have a bad high pressure fuel pump, low pressure fuel pump, or a bad fuel pressure regulator? The mechanic said his guages were showing a pressure fluctuation, but I don't know what his PSI reading was. I hooked my guage to it after cleaning everything and easily get over 50psi. My guage could be bad though. I don't trust it. I can run it with the muffs hooked to the hose and motor all day long with smooth operation and no alarm but as soon as I am in the water under load, the alarm will go off again if I try WOT. I also replaced all the fuel to make sure I didn't have a bad fuel problem. Any ideas?

 

[Fishing4fun]

Re: 2006 50hp EFI 4-stroke fuel problems

No ideas at all? Surely with all the experts here someone has at least 1 idea. Hooked it back to the computer again and the CDS did finally show a fuel sensor alarm. The "Certified" Mercury mechanic said it could be anything. This engine only has 28 hours on it and I feel warranty should be covering this and getting it fixed but the "Certified" Mercury mechanic still says that there is an obstruction somewhere and that isn't covered under warranty. I have been through every inch of the fuel system from the tank to the injectors. Every piece is absolutely spotless as a new engine should be. There are no leaks anywhere at all. The only place that I can't blow air through is the one fuel line that goes into the VST at the fuel pressure regulator. I am thinking that since the regulator is controlled by pressure that I shouldn't be able to blow air through there anyway. Is this the case or do I have a bad regulator causing the obstruction that the "certified" Mercury mechanic is talking about. If I have to keep paying someone to hook the CDS up at thier prices, I may as well start looking to buy a new motor. Maybe a Yamaha?